The values of the filling factor \(f\)  deduced herein are broadly consistent with stochastic acceleration models [1]}, [2]} which generally involve a near-homogeneous distribution of scattering centers. In addition, the deduced values of the specific acceleration rates \(\eta \)  are also broadly consistent with such models. For example, in their study of electron (and proton) acceleration in a turbulent magnetohydrodynamic wave cascade, [3]} derive values of the volumetric electron acceleration rate \(\sim (1.5 - 4) \times 10^8\)  cm\(^{-3}\)  s\(^{-1}\)  above 20 keV, with the exact value dependent on the assumptions of the various models considered. In the [3]} model, the background number density is \(n=10^{10}\)  cm\(^{-3}\) , so that \(\eta \sim (1.5 - 4) \times 10^{-2}\)  s\(^{-1}\)  above 20 keV.
